NEEMA Funded Projects by Topic Area – Viral Hepatitis
NEEMA 2.0 (2019-2024)
Only a fraction of hepatitis A, acute hepatitis B, and acute hepatitis C cases are reported through the National Notifiable Disease Surveillance System to CDC. There are several barriers to ascertaining and reporting acute infections, including the fact that many people with viral hepatitis infections may not develop symptoms, may not seek care if they become symptomatic, or may not be reported to public health authorities if they do receive medical care. Currently, CDC estimates the incidence of viral hepatitis A, B, and C infections using three probabilistic multiplier models. This project will update and improve the methodology used to estimate the incidence of acute viral hepatitis cases in three key ways. First, it will upgrade the structural model to a hierarchical framework and include covariates that can predict variation in each of the three adjustment factors (i.e., probabilities of symptoms, care-seeking, and capture in the surveillance system). Second, it will incorporate time series and stratum-specific estimates of underlying incidence and corresponding case notification data. Finally, it will focus on joint modeling of hepatitis A, B, and C incidence, including ascertainment and reporting, with synthesis of available evidence relevant to each and accounting for shared processes.
As of October 2019, widespread hepatitis A virus (HAV) outbreaks were ongoing in 30 states due to person-to-person transmission, resulting in more than 27,000 reported cases, and 275 deaths. Key populations at increased risk of infection are people who use drugs (PWUD), people experiencing homelessness (PEH), and men who have sex with men (MSM). Local health departments urgently require information on levels of vaccination needed to prevent outbreaks and achieve herd immunity. Previous studies estimating target vaccine coverage required to prevent HAV outbreaks have been limited to endemic transmission and universal vaccination as opposed to targets for specific populations at increased risk. This work will combine the state-level and national data on HAV outbreaks with dynamic modeling to understand herd immunity thresholds among, and transmission patterns between, PEH, PWUD, and MSM. Developing a tool for counties to use to estimate required vaccination numbers and the associated vaccination budget is also planned.
The most recent CDC hepatitis B screening recommendations were published in 2008. Since then, additional groups at increased risk (people co-infected with hepatitis C, people with current or history of sexually transmitted infections, people with current or history of incarceration) and testing strategies (HBsAg only; anti-HBc followed by HBsAg if anti-HBc-positive; HBsAg and anti-HBs; or HBsAg, anti-HBs, and anti-HBc) have emerged. Cost-effectiveness analyses for hepatitis B testing strategies in populations at increased risk will help inform the next CDC testing recommendations. This project will estimate the cost-effectiveness of hepatitis B testing in people with a history of or current STIs, a history of or current incarceration, or co-infection with hepatitis C, and will examine the cost-effectiveness of universal screening for people born before 1991 (time when universal hepatitis B vaccination recommendation was implemented). For each group, it will assess the cost-effectiveness of different testing algorithms based on various combinations of the 3 HBV seromarkers (HBsAg, anti-HBs, and anti-HBc).
CDC and the U.S. Preventive Services Task Force recommend one-time routine HCV screening for all adults (18 years and older). CDC continues to recommend people with risk factors, including people who inject drugs, be tested regularly. However, there is no evidence to inform the optimal testing interval for people at increased risk, or the cost or cost-effectiveness of intensive and frequent testing. This project will use a previously developed agent-based network model of HCV transmission across injection-drug-using networks to: identify the minimum HCV testing frequency needed to achieve HCV elimination among PWID, estimate the cost of such testing and treatment, and measure the cost-effectiveness of various testing frequencies.
As an increasing number of states are beginning to tackle state-wide hepatitis C elimination plans, the success of these initiatives is likely to depend on effectively addressing the high prevalence of HCV infection and its risk factors in correctional populations, including jails and prisons. Previous studies focused on evaluating a range of strategies for HCV testing and treatment in prisons and found that such strategies could provide high value for funds invested. Jails differ from prisons in several ways that present logistical and cost challenges for scaling up HCV testing and treatment. Jail sentence durations are typically short, meaning that most people who initiate HCV treatment in a jail will need to be linked to a treatment provider in the community upon release. Jails typically do not have available resources to support large-scale HCV treatment, or adequate infrastructure for monitoring patients and linking them to community care. This project will focus on optimizing HCV testing and treatment strategies in jails and the associated clinical and public health benefits of different strategies by identifying testing and treatment implementation models that provide good value for the resources invested in scale-up, and estimating budgetary impact from the jail perspective.
In the United States, injection is an increasingly common and high-risk route of administration for prescription and illicit opioids as well as other drugs such as methamphetamine. Unsafe injection drug use (IDU) behaviors increase risk for bloodborne infectious diseases such as HCV and HIV, making these infectious diseases secondary but deleterious consequences of the opioid crisis for people who inject drugs (PWID). Due to the stigmatized and illicit nature of non-medical IDU, population-level prevalence is difficult to measure using survey methods typically used to monitor health-related behaviors. Estimation of national population size of PWID is critical for informing infectious disease prevention efforts among PWID. The current national PWID population size estimate is based on household survey data from 2011 and does not reflect current opioid and methamphetamine injection. This project will update the PWID prevalence estimates nationally and for specific subpopulations of interest.
People who inject drugs (PWID) are at high risk for multiple blood-borne and sexually transmitted infections including HCV and HIV. National and state-level planning SSPs and MOUD programs rely on accurate estimation of PWID population size and understanding how these interventions impact HCV and HIV transmission among PWID. The particular structure of injection networks and sexual networks among PWID leads to heterogeneous risks of infection transmission and acquisition across the PWID population. In addition to SSPs and MOUD programs, many other preventive strategies are available for both HCV and HIV, including biomedical interventions (e.g., HIV pre-exposure prophylaxis, HIV treatment, HCV treatment) and behavioral interventions (e.g., promoting safer injection practices, condom use). Interventions can interact with each other and generate synergistic (or antagonistic) effects on the prevention of HCV and HIV infection. What determines the optimal intervention package is unknown. This project will extend the existing agent-based network model of HCV transmission among PWID to: (1) determine the levels of SSP coverage needed to reduce new HIV and HCV infections among PWID by 25%, 50%, and 90%; (2) compare the population health and economic impacts of different levels of program coverage for opioid use disorder; (3) identify intervention combinations among different prevention strategies that may produce substantial reductions in HCV and HIV burden among PWID; and (4) compare the cost-effectiveness of different intervention packages.
There are limited data and literature that describe the cascade of care for hepatitis B virus (HBV) infection in the United States. Past studies suggest many people with hepatitis B are not aware of their infection and that those who are eligible, are not receiving care and treatment. This project will collect up-to-date data on the hepatitis B cascade of care and evaluate the cost-effectiveness of improvements. Health system datasets will be used to better understand rates of, and costs of, screening, linkage to care, and treatment for those who are eligible. Modeling tools will be used to understand the current cascade of care for hepatitis B in the United States and evaluate the cost-effectiveness of portfolios of interventions to improve and increase rates of screening, linkage to care, and treatment for those who are eligible.